1. Technical Field
The present invention relates generally to satellite communications, and more particularly to a system and technique for combining MEO and LEO satellite constellations in a communication system for improved communications performance.
2. Discussion
Presently known satellite communication networks use either low-earth orbit (LEO), medium-earth orbit (MEO) or geosynchronous (GEO) satellite constellations to transfer voice, data or video signals from a source to a destination. Such satellite constellations have distinct advantages and disadvantages. For example, MEO orbits are optimized for multiple satellite diversity systems with low link margins. On the other hand, LEO satellites provide a higher link margin and support higher data rates into a given size subscriber unit because of their reduced path loss. However, a LEO based satellite communication system typically requires more satellites for a given coverage area. Accordingly, it is desirable to provide a satellite based communication system which utilizes LEO and MEO satellites for optimizing communication performance and services to the system subscribers. It is further desirable to provide a technique for deciding whether the LEO satellite or the MEO satellite is better for carrying the communication session with a particular subscriber.